Two-cycle gas engine



2 9 in Lf w M O. M. DE LUNTY TWO-CYCLE GAS ENGINE Filed June l0` 1920 2 Sheets-Sheet 1 .Irl 16 I @me dma: a? elafzuzj @i @y 1 im. Y 11.453,9

O. M. DE LAUNTY TWO- CYCLE GAS ENGINE Filed June l0 1920 2 Sheets-Sheet 2 Patented May 1, 1923.

Eiga@ OLIVER M. DE LAUNTY, OF. CHCAGO, ILLINOIS!y TWO-CYCLE GAS ENGINE.

Application filed June 10,

T @ZZ whom t may concern Beit known that I, OLIVER M. Dn LAUNTY, a citizen of the United States, and resident of Chicago, county of Cook, and State of Illinois, have invented certain new and useful Improvements in Two-Cycle Gas Engines, of which the following is a specification, and which are illustrated in the accompanying drawings, forming a part thereof.

The invention relates to gas engines and especially to two-cycle gas engines having shouldered pistons arranged in pairs with the shoulder of each piston serving as a pumping element for the delivery of explosive charges to the power chamber over the companion piston of the saine pair. The object of the invention is the improvement of gas engines of the type indicated, particular reference being had to the provision of a single intermediate compression chamber associated with each pair of cylinders and arranged for the admission of the explosive charges to the cylinders at their upper ends.

An illustrative embodiment of the invention is shown in the accompanying drawings, in which Fig. 1 is a side view, partly in elevation, partly in section on the central plane of the c linders and partly in section on the central p ane of said intermediate compression chamber;

Fig. 2 is a plan section taken on the line 'Fig 3 is a side view showing a rotating valve which may be employed for controlling the admission of the explosive charges to the pump chambers and their delivery to the cylinders, together with certain associated parts, some of the latter being shown in section;

Fig. 4 is in part a plan View and in part a horizontal section, the plane of the section being indicated'by the line 4 4 on Fig. 1; and

Fig. 5 is a detail sectional view taken on the line 5-5 of Fig. 4, but drawn ytoa larger scale.

The invention is shown as embodied in a four cylinder engine, its crank shaft being represented at 10, journal bearings, as 11, 12, and 13, and fly wheel at 14. The usual connecting rods extend between the cranks of the crank shaft 10 and the pistons 16, to the latter of which they are connected by the piston pins, as 17.

To provide pump chambers, as 18, and

exhaust manifold (not shown) 1920. Serial N'o. 387,861.

power chambers, as 19, each of the cylinders is bored to different diameters in different portions. The pistons 16 are accordingly formed with correspondingly small and large portions 20 and 21.` To make the pistons tight, piston rings 22 or 23 are applied to each part of the same, and a contracting ring 24 is preferably mounted in the wall of each power chamber 19 adjacent its lower end.

To simplify the assembly of the engine, parts of the cylinders comprising their larger portions are cast integral with the upper half of the crank case 25 and this integral casting preferably includes enough4 of the remainder of the cylinders to receive the contractile piston rings 24. The upper end portions of the cylinders, comprising the walls of the power chambers 19, on the other hand, are most conveniently cast two in a block and are formed with a water jacket. 26 for each block, such water jacket opening as at 27, for communication with a circulation conduit 28, having flanges 29 and 30 which are bolted to the said cylinder blocks. Bolts, as 31, within the water jackets and which may be reached by removal of the circulation conduit 28, serve in part for securing the cylinder blocks to the crank case casting. Other bolts 32, exposed upon the outside of the water jackets are also employed for holding the removable cylinder blocks in place.

The pistons and cylinders may be assembled by entering the pistons equipped with rings. 22 on their larger portions 21 tl'irough the crank case prior to the application ofthe removable bottom, as 33. rlhe contractile ring 24 will then be applied and next the rings 23 after which the cylinder blocks may be placed over the portions20` of the pistons.

Exhaust ports are shown at 34, and, as usual in two-cycle engines, they are so placed as to be uncovered by the corresponding pistons 16 as the latter approach the end of their downward strokes. The two exhaust ports 34 for each cylinder block preferably communicate with a single outlet 35 to which an may be bolted.

To provide for the admission to and delivery of the explosive charges from the pump vchambers 18, there are shown passages 36, 37, which passages are controlled by a rotating element generally designated 38 (Fig, 3) constituting a combined valve and intermediate pressure chamber, there being one such element for eac-h pair of cylinders.

Element 38 is shown as coacting with the squared end 42 of a vertical shaft 43, extending into the crank ease and journaled in bracket 44, for rotation at crank shaft speed by gears 45, 48, the latter of which is keyed directly to the crank shaft. The space within the element 38 is shown as divided into two parts by an imperforate diaphragm 39 thus providing the said intermediate pressure chamber, designated 40, and a second chamber 41 through which the gas passes from an inlet port 42, about which the intake. manifold or a carburetcr (not shown) may be bolted to the corresponding cylinder block. For inlet of gases to the chamber 41. the element 38 is formed with two ports 43 and 44, which ports register in alternation with the inlet port 42', leading from the carbureter.

To place the chamber 41 of the rotating valve element 38 in communication with passages 36 and 37, respectively, when the corresponding piston 16 is moving downward, the said valve element is termed with a single port opening 45a at its lower end. Under these circumstances, the lower end portion 46a or' the valve element 38 is preterably formed tapering, to provide a close fitting seat about the port 45a.

Since the pistons 1G of each pair move in opposite directions and there is but one port opening 45L in each valve element 38, the passage 36 or 37 is always shut oit Afrom the intake chamber 41 when the correspondingY piston 16 is moving upwardly. To provide an exit for the explosive charges from the pump chambers 18 and to store each charge .in the compression chamber 40 et valve element 38 for an instant during the revolution of the said valve element, passages 47, 48, (F ig. 5) are formed in the cylinder walls` the said passages constituting extensions ot passages 36 and 37, and the valve element 38 is formed with a port 49 which registers in alternation with the said passages 47, 48. As shown, the port 49 is so positioned about the axis of the valve element 38 with reference to the position ot port 45a (Fig. 3) that the chamber 40 of the valve element is in open communication simultaneously with passages 36 and 47, or 37 and 48, when the corresponding piston 16 is moving upwardly and communication of the passage 36 or 37 with space 41 is closed.

Preferably the larger portion 21 ot' each piston 16 is designed to lea-ve very little clearance in the corresponding pump chainber 18. lt follows that the amount of gas which lills one ot the pump chambers 18 and the pressure chamber 40 at substantially atmospheric pressure, will be practically all compressed into the pressure chamber when the corresponding piston approaches the end of its 11p-stroke.

To permit the gas compressed into cham-- ber 40 by one piston of theassociated pair to expand into the power' chamber 19 over Vthe other piston of the same pair, the valve element 38 is further provided with a port f' 50 opening from chamber 40 and registering in alternation with ports 51 and 52, leading into the power chambers 19. Port 50 is shown as being disposed 90O from port 49, while ports 51 and 52 are in vertical alignment with the upper ends of passages 47 and 48 respectively. lt therefore follows that a quarter ot a revolution of the valve element 38 after the full open position of port 49 to a pump chamber 18 oit one cylinder will bring the full open position of port 50 to the power chamber 19 of the other cylinder. l/Vhen the width of the ports is taken into account, port 50 will be seen to open very shortly after the closing of port 49.

The opening of portiy 50 to each cylinder will take place just at the time of, or immediately a't'ter, the uncovering of exhaust port 34 ot the same cylinder. The explosive charge confined in chamber 40 under pressure will therefore rush into the power chamber ot the cylinder at the top and assist in scavenging that chamber as well as filling it for the compression stroke of the piston. Port 50 is shown as quite narrow since it must not open in advance of the opening of the exhaust port 34 and yet must close before the piston 16 makes any appreciable upward movement. rlhere will therefore be short intervals during the upward strokes of each piston when the ports 49 and 50 will both be closed from the chambers affected by the piston. Baring this interval an explosive charge will be slightly compressed in the corresponding' pump chamber 18 and will then the more quickly rush into the chamber 40 when the port 49 opens. During the entire power stroke of each piston the single intake port 51 or 52 of the corresponding power chamber will be closed by registration therewith of a solid part of the wall of the valve element 38. f

Since the shaft 43 and valve element 38 are rotated at crank shaft speed it is possible to utilize the element 38 to operate an ignition device. For this purpose a stud shaft 53 is shown projecting from the top of the element 38 and a device 54 'which may be either a magneto or a distributor or an Op erating device for either, is indicated as carried by the stud shaft. The bores in the cylinder blocks for receiving the valve ,elements 38 preferably extend through the tops ot the blocks at one sidewof the openingsr to which thekwater circulation conduit 28 is applied. lr', therefore, the said valve ele-V ments are held to their seats by screw threaded plugs, as 55. they may be easily re` moved at any time for inspection, cleaning or renewal. As shown, each of the stud shafts 53 extends through and is journaled in one of the plugs 55. There being two of lthe elements 38 in a four cylinder engine,

it is possible to equip such an engine with both a distributor and a magneto, or the stud shaft 53 may be omitted from one element 38, if desired, and the plug made imperforate, as shown at 56, Fig. 4.

It' the intake ports 5l and 52, be made of the form indicated in Fig. 2, and the spark plugs are located as indicated at 57 and 58, the spark plug will project into the ports and will be swept by the ingoing gases and will be certain to be surrounded by a part of the fresh charge to give the most efficient ignition.

The bore for reception of the valve element 38 is shown as placed in each block of cylinders, partly between the smaller diameter portions of the cylinders and as being contained within the water jacket Without necessitating any projection at the side or' the cylinder block. On the other hand, through the extent oi' the portions of larger diameter of the cylinders, only the shaft 43 has to be accommodated and ample space exists for this shaft. This arrangement makes for compactness and symmetrical appearance. Moreover, since the chamber 4:0 of each valve element 38 is surrounded by the heated water in the jacket, tendency for fuel to condense therein is lessened.

I claim as my invention:

l. In a gas engine, the combination with a common cylinder block chambered to provide a pair of upright power cylinders each having pump and explosion chambers, an exhaust port at the lower end of the explsion chamber of each power cylinder, an intermediate upright cylinder for a rotating valve element, an intake port opening into the side of the valve c linder adjacent its lower end, passages lea ing from the lower end of the valve cylinder to the pump cham-y er section of the valve controlling the said intake port, a single port in the lower end of the valve controlling the said two passages leading to the pump chambers of the power cylinders, a single port in the upper section of the valve controlling the said two extension passages and a single port in the upper section of the valve controlling the said two passages leading to the eX- plosion chambers of the power cylinders.

2. In a gas engine, in combination with a common cylinder block chambered to provide a pair of upright power cylinders and an intermediate upright cylinder for a rotating valve element opening through the top of the cylinder block, of pistons operating in the power cylinders, a crank shaft operated by the pistons, an upright shaft turning with the crank shaft and entering the valve cylinder through the lower end of the same, a valve turning in the cylinder, its lower end removably engaging the upper end of said upright shaft, and rotated therewith, and a removable screw plug closing the upper end of the valve cylinder over the valve.

OLIVER M. DE LAUN TY. 

